From: Michal Hocko <mhocko@kernel.org>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
David Rientjes <rientjes@google.com>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm,oom: Bring OOM notifier callbacks to outside of OOM killer.
Date: Fri, 6 Jul 2018 07:39:42 +0200 [thread overview]
Message-ID: <20180706053942.GF32658@dhcp22.suse.cz> (raw)
In-Reply-To: <20180703160101.GC3593@linux.vnet.ibm.com>
On Tue 03-07-18 09:01:01, Paul E. McKenney wrote:
> On Tue, Jul 03, 2018 at 09:24:13AM +0200, Michal Hocko wrote:
> > On Mon 02-07-18 14:37:14, Paul E. McKenney wrote:
> > [...]
> > > commit d2b8d16b97ac2859919713b2d98b8a3ad22943a2
> > > Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> > > Date: Mon Jul 2 14:30:37 2018 -0700
> > >
> > > rcu: Remove OOM code
> > >
> > > There is reason to believe that RCU's OOM code isn't really helping
> > > that much, given that the best it can hope to do is accelerate invoking
> > > callbacks by a few seconds, and even then only if some CPUs have no
> > > non-lazy callbacks, a condition that has been observed to be rare.
> > > This commit therefore removes RCU's OOM code. If this causes problems,
> > > it can easily be reinserted.
> > >
> > > Reported-by: Michal Hocko <mhocko@kernel.org>
> > > Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
> > > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> >
> > I would also note that waiting in the notifier might be a problem on its
> > own because we are holding the oom_lock and the system cannot trigger
> > the OOM killer while we are holding it and waiting for oom_callback_wq
> > event. I am not familiar with the code to tell whether this can deadlock
> > but from a quick glance I _suspect_ that we might depend on __rcu_reclaim
> > and basically an arbitrary callback so no good.
> >
> > Acked-by: Michal Hocko <mhocko@suse.com>
> >
> > Thanks!
>
> Like this?
Thanks!
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-07-06 5:39 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-20 11:20 [PATCH] mm,oom: Bring OOM notifier callbacks to outside of OOM killer Tetsuo Handa
2018-06-20 11:55 ` Michal Hocko
2018-06-20 12:21 ` Tetsuo Handa
2018-06-20 13:07 ` Michal Hocko
2018-06-25 13:03 ` peter enderborg
2018-06-25 13:07 ` Michal Hocko
2018-06-25 14:02 ` peter enderborg
2018-06-25 14:04 ` peter enderborg
2018-06-25 14:12 ` Michal Hocko
2018-06-20 22:36 ` David Rientjes
2018-06-21 7:31 ` Michal Hocko
2018-06-21 11:27 ` Tetsuo Handa
2018-06-21 12:05 ` Michal Hocko
2018-06-26 17:03 ` Paul E. McKenney
2018-06-26 20:10 ` Tetsuo Handa
2018-06-26 23:50 ` Paul E. McKenney
2018-06-27 10:52 ` Tetsuo Handa
2018-06-27 14:28 ` Paul E. McKenney
2018-06-27 7:22 ` Michal Hocko
2018-06-27 14:31 ` Paul E. McKenney
2018-06-28 11:39 ` Michal Hocko
2018-06-28 21:31 ` Paul E. McKenney
2018-06-29 9:04 ` Michal Hocko
2018-06-29 12:52 ` Paul E. McKenney
2018-06-29 13:26 ` Michal Hocko
2018-06-30 17:05 ` Paul E. McKenney
2018-07-02 12:00 ` Michal Hocko
2018-07-02 21:37 ` Paul E. McKenney
2018-07-03 7:24 ` Michal Hocko
2018-07-03 16:01 ` Paul E. McKenney
2018-07-06 5:39 ` Michal Hocko [this message]
2018-07-06 12:22 ` Paul E. McKenney
2018-06-29 14:35 ` Tetsuo Handa
2018-06-30 17:19 ` Paul E. McKenney
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